Extraskeletal myxoid chondrosarcoma. A clinicopathological study

Abstract

Extraskeletal myxoid chondrosarcoma is a rare tumor of cartilagenous origin, with only 41 previously reported cases. It has a distinctive histologic pattern and should be distinguished from chondrosarcoma of bone because of its different behavioral pattern. The light microscopic, histo-chemical and electron microscopic features of such a tumor are reported.

Extraskeletal myxoid chondrosarcomas do not show a chondrocytic phenotype

“…29 These results specify biochemically previous ultrastructural findings that described the extracellular matrix of extraskeletal myxoid chondrosarcoma as consisting mainly of amorphous material with few collagen fibrils. 16 Our findings indicate that these fibrils are composed mainly of collagen types I and III. The fine fibrillar networks between them seem to consist, at least in part, of collagen type VI.…”

“…Also the classification of primitive or undifferentiated mesenchymal cells as chondroblastic by electron microscopy has to be considered with caution, 16 as demonstrated recently for chondroblastomas. 25 Chondroblastomas do not show chondroblastic differentiation despite morphological and ultrastructural resemblance to chondroblastic cells.…”

“…7,8 The histopathologic spectrum of extraskeletal myxoid chondrosarcoma ranges from lesions with densely packed rounded cells to those composed of cords of cells and lesions with focal cartilage formation. 2 This cartilage formation, the originally reported positivity for S-100 protein, [9][10][11][12][13][14][15] and the ultrastructural resemblance of the neoplastic cells to chondroblasts 13,16 were the source of the term 'extraskeletal myxoid chondrosarcoma' for this type of soft-tissue tumor. 17 However, most extraskeletal myxoid chondrosarcomas do not show chondroid tissue formation.…”

Intra-articular extraskeletal myxoid chondrosarcoma of the ankle

“…However, it was not until 1972 that EMC was histopathologically defined as its own entity [9]. EMC is a relatively rare and unusual soft tissue sarcoma accounting for less than 2 % of all soft tissue sarcomas [3] and was originally termed 'chordoid sarcoma' based on its histological resemblance to chordoma [10].…”

“…It is a relatively rare but wellcharacterized tumor that usually arises in the deep soft tissue of the extremities [2] and accounts for less than 2 % of all soft tissue sarcomas [3]. It is distinguished from other sarcomas by its unique histology and a characteristic chromosomal translocation.…”